The objectives of this proposed research are to: a) determine the relationship between compensatory speech patterns and aerodynamic events in cleft palate and severe malocclusion; b) determine the effects of changes in oral dimensions on oral/nasal resonance and voice quality; c) determine the effects of maxillary osteotomy on airway breathing patterns and speech; d) develop models of disordered speech based on clinical findings. The pressure-flow technique will be used with acoustic, palatographic and preceptual approaches to document, quantify and relate physiologic, aerodynamic and acoustic events during speech. A computer based data collection and analysis system will monitor and store a variety of data simultaneously and process any combination using recent digital techniques.